A supercharger (blower) is an air compressor that forces more air and, thus, more oxygen into the combustion chamber(s) of an internal combustion engine than achievable with ambient atmospheric pressure (natural aspiration).

The additional mass of oxygen-containing air that is forced into the engine improves on its volumetric efficiency which allows it to burn more fuel in a given cycle�which in turn makes it produce more power. A supercharger can be powered mechanically by belt, gear and shaft, or chain-drive from the engine's crankshaft. It can also be driven by a gas turbine powered by the exhaust gases from the engine. Turbine-driven centrifugal superchargers are correctly referred to as turbo-superchargers�or more commonly as turbochargers.

Types of supercharger

There are two main types of supercharger defined according to the method of compression, positive displacement and dynamic compressors. The former deliver a fairly constant level of boost regardless of engine speed (RPM), whereas the latter deliver increasing boost with increasing engine speed.

Positive displacement

Positive displacement pumps deliver a nearly fixed volume of air per revolution at all speeds (minus leakage which is nearly constant at all speeds for a given pressure and so its importance decreases at higher speeds). The device divides the air mechanically into parcels for delivery to the engine, mechanically moving the air into the engine bit by bit.

Positive displacement pumps are further divided into internal compression and external compression types.

Roots superchargers are typically external compression only (although high helix roots blowers attempt to emulate the internal compression of the Lysholm screw).

* External compression refers to pumps which transfer air at ambient pressure into the engine. If the engine is running under boost conditions, the pressure in the intake manifold is higher than that coming from the supercharger. That causes a back flow from the engine into the supercharger until the two reach equilibrium. It is the back flow which actually compresses the incoming gas. This is a highly inefficient process and the main factor in the lack of efficiency of roots superchargers when used at high boost levels. The lower the boost level the smaller is this loss and roots blowers are very efficient at moving air at low pressure differentials, which is what they were first invented for (hence the original term "blower").

The turbo whistler is an aluminum device which
easily fits inside your car or trucks muffler exhaust pipe. Under heavy
acceleration makes your car sound like it has a fake turbocharger. In some cars
letting off the gas pedal releases backpressure in the muffler making the car
sound like it has a small blow off valve. All your friends will think you have a
turbocharger under your hood!

TURBO WHISTLER WORKS ON ALL
CARS!

The best part about our turbo whistler is that
it only takes seconds to attach. No welding or drilling needed. You can
easily detach the exhaust whistler and hear the turbo sound on all your friend's cars!

The turbo whistler measures about 3" long
and is made of lightweight aluminum.